Process of extracting copper from its ores



. NiTED STATES GEORGE GOETZ, OF MILWAUKEE, WISCONSIN.

PROCESS OF EXTRACTIN G COPPER FROM ITS ORES.

SPECIFICATION forming part of Letters Patent No. 519,111, dated May}, 1894.

Application filed September 19 1893- Serial No. 485,873. (No specimens.)

. To aZZ whom it may concern.-

Be it known that I, GEORGE W. GOE'1z,of Milwaukee, in v the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Processes'of Extracting Copper from its Ores; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it pertains to make and use the same.

It is well known that copper oxides have been dissolved by placing them in a solution of sulphate of iron and chloride of sodium, a quite strong solution being generally employed although the strength of the solution may widely vary and yet produce the required result. The mixed solution of sulphate of iron and chloride of sodium will dissolve the oxides of copper and metallic copper may be precipitated from the solution by introducing metallic iron, usually in the shape of scrap iron. The introductionof the metallic iron causes the copper to be precipitated in a finely divided state which is ordinarily called cement copper.

The process just described is known in metallurgy as the Hunt and Douglas process.

,d It has been attempted to extract copper tailings containing metallic copper by first roasting them, so as to oxidize the copper, but it has been found that the oxidation-was incomplete, the coating of oxide formed by roasting protecting the interior of the copper from further oxidation in the furnace, and when the solution as ordinarily employed is applied to the roasted tailings only the exteriorcovering of copper oxide is dissolved, leaving the metal intact, or so very slightly acted upon that the process is useless for the purposes of extraction. Metallic copper or sulphide of copper is not acted upon, or only slightly so, in a solution of sulphate or chloride of iron and chloride of sodium even if the mixture of ore and solution are violently agitated by mechanical means,because hardly any oxidation can take place; but the introduction of a strong air blast will bring about a strongly oxidizing influence with the resulting solution of the copper.

/In myimproved process,I take a strong solution of sulphate of iron and sufficient chloride of sodium to produce chloride of iron with an excess of the chloride of sodium, and introduce into it a quantity of copper tailings or ore, which consists either of finely divided metallic copper or sulphide of copper, and the dross, rock or matrix in which it is found.

ing material is such, that the resulting mixture should be thin, for the hereinafter de scribed manipulations. It should not be so thick as to prevent the rapid ebullition of the component mass under the after treatment. After this has been done, I introduce at the bottom of the mixture a blast of air in sufficient force and quantity to create rapid mechanical agitation of the mixture and cause the air to agitate and come in contact with every portion thereof. This causes a very rapid dissolving of the copper in the copper is in a metallic state. Aftersufficient time has elapsed to dissolve the copper, which is usually from one to two hours, I stop the 'air blast and separate the solution from the earthy matters by allowing it to settle, or by filtration, and add to the clear solution obtained, scrap iron, which causes the copper to precipitate as-cement copper. The quantity of iron added is preferably largely in exface as possible, in order to expedite the precipitation of the copper. deprived of copper and regenerated by the addition of the iron, can be used over again as described, in connection with the air blast. The process is thus practically continuous, the solution of chloride of iron and chloride of sodium once formed by the mixture of sulphate of iron with chloride of sodium in excess as hereinbefore explained, being used over and over again, after having dissolved the copper, had the copper precipitated from it by the addition of scrap iron, again dis- The solution thus The proportion of solution and copper beartailings or ore, and especially so when the cess and in forms affording as great a sur- IOO solving the copper under the influence of the air blast, and so on. There is of course a loss of solution from adhesion to the earthy matters and the cement copper, when it is withdrawn,but the loss is slight. The quantity of air supplied and the force of the blast does not require to be regulated within narrow limits, it being only necessary to introduce the air in the solution under such pressure and in such quantities as will produce a violent agitation of the mixture and prevent the settling of the copper tailings or ore, thus giving each little particle of copper an opportunity to become oxidized, which then makes it soluble in the above mentioned solution.

I believe that I have discovered the fact that copper is oxidized in a solution of chloride of iron and chloride of sodium by means of an air blast, most of the copper-being in the solution finally as sub-chloride of copper. It will be obvious to those familiar with the art to which my invention pertains, that the chloride of iron and chloride of sodium are the active agents in carrying out my process, and that the chloride of iron can be produced by dissolving iron in hydrochloric acid, or otherwise, the sulphate of iron being employed simply from economical considerations to produce the initial solution. The excess of chloride of sodium in the solution serves to hold in-solution any sub-chloride of copper that is formed and would otherwise be precipitated and mixed with Waste products.

I claim- 1. The process of extracting copper from copper tailings'or ore, consisting in mixing the combined copper and foreign substances with a solution consisting principally of chloride of iron and chloride of sodium, and introducing air underneath the mixture so as eign substances, consisting in the mixing of the copper and foreign substances with a solution of chloride of iron and chloride of sodium, the introduction of air beneath the surface of the mixture so as to agitate the same, and the precipitation of the copper from the resulting solution by the introduction of metallic iron and the re-use of the solution separated from the copper in'again similarly reducing other ores, substantially as and for the purposes described.

4. The process of extracting copper from copper tailings or ore, consisting in mixing the combined copper and foreign substances with a solution of chloride of iron and chloride of sodium,produced bya mixture of sulphate of iron with an excess of the chloride GEORGE W. GOETZ.

Witnesses:

A. W. EMERY, OHAs. L. Goss. 

